Moving luminescent screen oscillograph



Feb. 24,1942. G, ASHE m; 2,274,182

MOVING LUMINESCENT SCREEN OSCILLOG'RAPH Filed Nov. 21, 1938 Ml EZECTPQCABDIQGEAPH /26;MZO

INVENTORS ATTORNEYS Patented Feb. 24, 1942 i ENT j OFFICE MOVING LUMINESCIJNT SCREEN a r OSCILLOGRAPH GrahamfAsher and Frank E. Hoecker, Kansas City, Mo. l

7 Application November 21, 1938, Serial No. 241,572

2 Claims. (o1. 1.28-4.06)

This invention relates to apparatus adaptable to the study of any low frequency or noncyclic phenomena which can produce a galvanometerdeflection, and which is particularly useful when combined with the conventional electrocardiograph to permit instant visualization of the electrical behavior of the heart, and the primary object of the invention is to provide a separate unit adaptable to electrocardiograph machines now in use so that simultaneous photographing and visualizing of the tracing may take place.

Another important aim of this invention is to provide a moving luminescent screenoscillograph adaptable for use with electrocardiographic ap' paratus to permit continuous observation of the Wave form to be studied.

A yet further aim of this invention is to provide a unit of the aforementioned character wherein is disposed a specially formed endless luminescent screen, a source of light,*a mirror galvanometer, and other structure for directing a light ray upon the" moving luminescentscreen, said galvanometer being electrically connectedto the amplifying apparatus of an electrocardiograph so that visualization of the electrocardiogram can be afforded simultaneously with or separate from the photographing thereof by the eleotrocardiograph.

The embodiment of the oscillograph, .shown in the accompanying drawing, is adaptablefor many purposes and especially for use with electrocardiograph machines now in use-without alteration thereof and merely by electrically con- Fig. 2 is a vertical central section throughthe same, taken on line II-II of Fig. 1..

Fig. 3 is an inside face view of one wallfof the caseof the unit.

Fig. 4 is a fragmentary sectional view taken on line IV?IV of Fig-3.

Fig. 5 is a wiring diagram; and,

Fig.6 is a schematic view showing an endless luminescent screen made in accordance with the modified form of the invention. In constructing the unit embodying this invention, a case 8 should be provided to house the endless luminescent screen l0 so that-it is within a darkened chamber l2 in order to permit great contrast between the wave form produced on the sensitive face ofthe endless screen II] .by the lightbeam. Case B,therefore, may be a box-like structure having a viewing aperture l4 therein along one side, whichaperture maybe closed by cover it when the. apparatus is not in use.

One wall [8 of case 8; should be hingedly or otherwise removably mounted to permit assembly, and it is onthis wall-l8 that the mirror galvanometer 29, the lamp,22 and shield 24, are

' mounted.

Mirror galvanometer 29 is electrically connectedby wires 26 and 28 to the amplifying apparatus of the conventional electrocardiograph,

not here shown but which is such as disclosed,

for example, in Patent No. 1,837,913, issued Denecting the mirror galvanometer of this unit with the amplifying apparatus of the electrocardiograph, which raises the voltage of the body to a point where galvanometer deflection is possible.

It is a further object of this invention to overcome many of the defects of operation which have been heretofore associated with cathode-ray oscillograph circuits and besides accomplishing this object, the apparatus presents a unique feature of having an endless luminescent screen upon which the wave form to be studied appears as a bright, glowing line on a dark background.

Specific objects and method of operating and associating the unit with existing means of measuring or indicating small voltages, will appear during the course of the following specification, referring to the accompanying drawing wherein:

Figure 1 is a front elevation of a moving luminescent screen oscillograph, made to embody the present invention.

in U

50 the peaks of the wave will cember 22, 1931. -In connecting galvanometer 20 to 'the electrocardiograph amplifier, or other source of voltage to be converted into a visible 'waveform for viewing, any other galvanometer 5 of the electrocardiograph may be dispensed with by omitting it from the electrical circuit.

, Mirror 30 of galvanometer 20 moves with the coil of the galvanometeryand in the instance diagrammatically illustrated herewith, the galvanometer is of the moving coiltype, buta sus pended magnet type may be used.

Lamp 22 has its rays directed onto mirror 30 through aperture 32 are projected along a the lines 34 to a lens 36 which overhangs the sensitized surface of endless screen I 0.

A knob 38, mechanically joined to mirror 30 by crank 40, permits manually adjusting the light beam so that as the wave form is created, not fall beyond the edges of screen l0.

Shield 24 confines the view of the operator so that only a relatively small portion of the coated face may be seen at any one time. This'shield 24 also protects the eye of the operator from andthen these light rays path of travel indicated by 7 Figs. 1 and 2, the endless luminescent the glow of lamp 22 and the beams of light emanating therefrom. Lamp 22 should be of relatively low voltage, and in practice, an automobile headlight lamp has proven satisfactory.

A transformer 42, housed within case 8, is connected to a source of power that is usually 110 volt and this transformer 42 serves to reduce this voltage to approximately 8 so that lamp 22 may function.

In the preferred embodiment, illustrated in screen 10 is in the nature of an open sided drum or dishshaped member which is rotatably mounted for movement about its axis, as shown in Fig. 2. A hearing 44 at the axis of drum 46 serves to so mount the member and the endless annular side of the drum becomes the endless. screen 10. This drum is made of sheet metal so that after lens 36 has once been focused on the inner annular face vof the side thereof, it will not flex and thusdistort the wave being viewed.

The coating43 which is applied to the inner annular continuous face of screen I0, is composed of luminescent zinc sulphide crystals which contain the impurities that are not only essential to the physical property of the luminescence, but also determine the color of the glow. It has been found that yellowish-red or red pro- 24, are. all confined within a space set off or circumscribed by screen I0. This feature in a unit embodying the present invention, is important, for it is contemplated that the oscillograph may be portable and light. The use of such a unit eliminates the necessity of transporting a much heavier machine in the nature of an electrocardiograph, and the size of the unit permits availability in operating rooms and other places where space occupancy is a factor.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1; A moving luminescent screen oscillograph for electrocardiographs, having apparatus for amplifying voltage, comprising a portable case provided with a viewing aperture; an endless luminescent screen movably mounted within the cluce best results, and the crystals retain their property of luminescence without loss for many months. In this connection, the luminescent material just mentioned, deteriorates much less than the material subjected to the cathoderay, heretofore employed in the art.

,A synchronous motor 48 drives endless screen I 'lll' through the medium of belt 50, which is extendedaround the outer annular face of screen It and over pulley 52 driven by motor 48. This motor may be geared to provide a range of speeds of the screen in order to provide for viewing a wide range of frequencies.

' The circumference or length of endless screen it is. such as to permit the complete loss of the glow caused thereon by the beam before a given point on the screen passes the line of vision of 'the'operator a second time.

' f Fig. 6 illustrates an endless screen having different physical in Figs. 1 and 2. '60 is of flexible material and is carried by a characteristics than that shown In this case, the endless screen number of rollers 62, one of which is mounted upon shaft 64 of synchronous motor 66, so that the screen may be driven in a continuous fashion. Obviously, a screen of this character may be substituted for the drum type screen 10, hereinabove described.

compactness of the unit is insured as a result of the overhanging relation between screen l0 and the parts of the unit mounted upon wall l8. Galvanometer 20, lamp 2.2, lens 36 and shield case; a source of light in the case; a mirror galvanometer electrically connected to the amplifying apparatus of the associated electrocardiograph; a lens between the luminescent screen and said galvanometer to concentrate and direct the light beam from the mirror of the galvanometer onto the endless luminescent screen; and means for driving the said screen, said endless luminescent screen being a dish-shaped drum pivotally supported at its axis, and having a coating of luminescent material over the inner annular face of the side thereof, said source of light, the galvanometer and the said lens being grouped within a space circumscribed by the side of said drum, said case having a shield therein between the viewing aperture and the side of said drum to confine the operators view to but a relatively small portion of the coated face of the drum during any one time.

2. A moving luminescent screen oscillograph for electrocardiographs, having apparatus for amplifying voltage, comprising a portable case provided with a viewing aperture; an endless luminescent screen movably mounted within the case; a source of light in the case; a mirror galvanometer electrically connected to the amplifying apparatus of the associated electrocardiograph; a lens between the luminescent screen and said galvanometer to concentrate and direct the light beam from the mirror of the galvanometer onto the endless luminescent screen; and means for driving the said screen, said case having :a shield therein between the viewing aperture and the luminescent screen to confine the 'operators view to but a relatively small portion 

